Cutter bit cluster and supporting means therefor



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Feb. 3, 1959 c. w. FITZGERALD 2,872,172

CUTTER BIT CLUSTER AND SUPPORTING MEANS THEREFOR Filed De c. 20, 1956 mvau'roai CHARLES w. FITZGERALD United States Patent A "CUTTER BIT CLUSTER AND SUPPORTING MEANS THEREFOR Charles W. Fitzgerald, Franklin, Pa., assignor to Joy Manufacturing Company, Pittsburgh, Pa., a corporation of Pennsylvania Application December 20, 1956, Serial No. 629,681

6 Claims. c1. 26 2-33) This invention relates to a cutter bit arrangement and more particularly to supporting and holding means for a cluster of cutter bits.

The present invention resides more particularly in an improved supporting and holding means for a cluster of cutter bits which may be carried by a single holder in a minimum of space using one lock to fasten all of the bits of the cluster on a common support. Such bit cluster arrangement is especially designed for use in mining machine cutter chains or with the boring heads of a continuous mining machine.

An object of the present invention is to provide an improved cutter bit arrangement and supporting and holding means therefor. Another object is to provide an improved cluster of cutter bits supported in a single holder and secured in place by but a single locking element. A further object is to provide an improved cluster of cutter bits mounted on a common support with one bit acting on the others to hold the bits in cutting position. A still further object is to provide an improved cluster of three cutter bits adapted for mounting on a common holder with the forwardly located one of the bits engaging the other two and with but a single setscrew serving to secure all three bits in cutting position on the holder. These and other objects and advantages of the invention will, however, hereinafter more fully appear.

In the accompanying drawing there is shown for purposes of illustration one form which the invention may assume in practice. 1

In this drawing:

Fig. 1 is a side view, with parts in central longitudinal section, of a cutter chain equipped with the improved cutter bit arrangement.

Fig. 2 is a top plan view of the cutter chain and bit arrangement shown in Fig. 1.

Fig. 3 is a transverse longitudinal section taken on line 3-3 of Fig. 1.

Fig. 4 is a front end view of the improved cutter chain and bit arrangement.

Fig. 5 is a central longitudinal vertical section taken on line 5-5 of Fig. 2.

Fig. 6 is a rear view of the forwardly located cutter bit showing its rear wedging surface.

Fig. 7 is a front view of one of the rearwardly located cutter bits.

Fig. 8 is a side View of the bit shown in Fig. 7.

Fig. 9 is a rear view of the rear cutter bit shown in Figs. 7 and 8.

In the drawing, a cutter chain for mining machines is shown although, evidently, the invention may be embodied in mining machines of other kinds such as a continuous mining machine of the rotary boring head type. The cutter chain is of a conventional design and is desirably made up of a series of chain blocks 1 pivotally connected by hinge pins 2 to strap links 3. Each chain block has a lateral lug 4 provided with a socket 5 for receiving a cluster of cutter bits respectively designated 6, 7 and 8, held in position by a setscrew 9. The cutter bits'have shanks 10 and cutting portions 11 terminating in cutting points 12.

The three cutter bits of the cluster comprise the two rear bits 7 and- 8 and the front bit 6 and the socket 5'has a laterally enlarged rear portion 13 (Fig. 3) for receiving the rear bit shanks and a relatively narrow forward portion 14 for receiving the shank of the front bit. The front bit has a straight cutting portion while the rear bits desirably have oppositely inclined cutting portions, as shown in Fig. 4. The shank of the front bit has a rear we'dgelike portion providing relatively inclined surfaces 15 extending along'lines converging rearwardly and the rear bits have forwardly facing, relatively inclined, complemental surfaces 16 which are engaged by the rear wedging surfaces 15 of the front bit. .The setscrew 9 engages the front face of the shank of the front bit and, when tightened, thrusts the front bit rearwardly in its socket to clamp the rear bits rearwardly against the rear socket wall and as the rear bits are thrust rearwardly the diverging surfaces 15 of the front bit act on the inclined surfaces 16 of the rear bits concurrently to force the latter apart against the side walls of the enlarged rearward portion of the socket. Thus the single setscrew 9 firmly secures the three bits in cutting position on the a single setscrew. The novel bit arrangement enables positioning of the bits in a minimum of space. Other advantages will be clearly apparent to those skilled in the art.

While there is in this application specifically described one form which the invention may assume in practice, it will be understood that this form of the same is shown for purposes of illustration and that the invention may be modified and embodied in various other forms without departing from its spirit or the scope of the appended claims.

What I claim as new and desire to secure by Letters Patent is:

1. In combination, a support having a socket, a cluster of three cutter bits comprising a front bit and a pair of rear bits having shanks received in said socket, the front bit engaging the rear bits, the shank of said front bit having a rearward wedge portion concurrently acting on the shanks of the rear bits, and an adjustable element on said support engaging the front bit for clamping all three bits firmly in cutting position on said support.

2. A combination as set forth in claim 1 wherein the rear bits have oppositely inclined surfaces on the front faces of their shanks and said wedging portion of said front bit shank has oppositely inclined wedging surfaces contacting said first mentioned surfaces to eifect wedging of the rear bits firmly into position.

3. A combination as set forth in claim 2 wherein said adjustable clamping element consists of a setscrew threaded on the support and engaging the front face of the shank of said front bit.

4. A cutter bit cluster adapted to be attached to a support and comprising a front bit and a pair of rear bits, said bits respectively having shanks and the front faces of the rear bit shanks being longitudinally cut away to receive the rear portion of the shank of the front bit so that the rear edge of the front bit shank is located rearwardly of the front edges of the rear bit shanks when the bit cluster is disposed in cutting position on the support said front bit when movedhrearwardly serving to clamp said rear bits rearwardly in position on the support, said rear bits being disposed at opposite sides of the longitudinal median plane of the bit cluster including the longitudinal median line of the front bit shank, said front bit having means, as said front bit is moved rearwardly, cooperating with means on said rear bits to thrust the latter apart for imparting a lateral clamping action to said rear bits against the support in addition to said rearward clamping action.

5. In combination, a support having a socket, a cluster of three cutter bits comprising a front bit and a pair of rear bits, said bits having shank-s received in said socket,

wedging means actuated by said front bit and acting on said rear bits for securing the latter in position on said support against the side and rear walls of said socket, an adjustable means engaging said front bit for causing actuation of said wedging means.

6. A combination, as set forth in claim 5, wherein said wedging means comprises a central wedge portion actuated by said front bit and coacting opposed wedging surfaces on the shanks of said rear bits.

References Cited in the file of this patent UNITED STATES PATENTS 

